Im a babysitter and I nee help...?

My boss who isn't married but is in a relationship with his live in girlfriend(my other boss) keeps making pass at me! I would of quite by now but it is $12/ hour and it is really hard for a college student to find a job. At first it was real little like he would tell me i was pretty and how he couldn't believe I was single. But now it is much more blunt! Like he knows how desperate I am for money and has basically offered me money for sex and I said no. But how can I keep working when its so uncomfortable? I really need the money!